
#include <vtkActor.h>
#include <vtkCellArray.h>
#include <vtkCommand.h>
#include <vtkContourFilter.h>
#include <vtkFloatArray.h>
#include <vtkImageData.h>
#include <vtkInteractorStyleUser.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkOutlineFilter.h>
#include <vtkPointData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSliderRepresentation.h>
#include <vtkSliderRepresentation3D.h>
#include <vtkSliderWidget.h>
#include <vtkXMLImageDataWriter.h>

namespace {
    void CreateData(vtkImageData* data);

    class vtkSliderCallback : public vtkCommand
    {
    public:
        static vtkSliderCallback* New()
        {
            return new vtkSliderCallback;
        }
        virtual void Execute(vtkObject* caller, unsigned long, void*)
        {
            vtkSliderWidget* sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller);
            double value =
                    static_cast<vtkSliderRepresentation*>(sliderWidget->GetRepresentation())
                            ->GetValue();
            this->ContourFilter->GenerateValues(1, value, value);
        }
        vtkSliderCallback() : ContourFilter(NULL)
        {
        }
        vtkContourFilter* ContourFilter;
    };
} // namespace

int main(int, char*[])
{
    vtkNew<vtkNamedColors> colors;

    vtkNew<vtkImageData> data;
    CreateData(data);

    // Create an isosurface
    vtkNew<vtkContourFilter> contourFilter;
    contourFilter->SetInputData(data);
    contourFilter->GenerateValues(1, 10,
                                  10); // (numContours, rangeStart, rangeEnd)

    // Map the contours to graphical primitives
    vtkNew<vtkPolyDataMapper> contourMapper;
    contourMapper->SetInputConnection(contourFilter->GetOutputPort());

    // Create an actor for the contours
    vtkNew<vtkActor> contourActor;
    contourActor->SetMapper(contourMapper);
    contourActor->GetProperty()->SetLineWidth(5);

    // Create the outline
    vtkNew<vtkOutlineFilter> outlineFilter;
    outlineFilter->SetInputData(data);

    vtkNew<vtkPolyDataMapper> outlineMapper;
    outlineMapper->SetInputConnection(outlineFilter->GetOutputPort());
    vtkNew<vtkActor> outlineActor;
    outlineActor->SetMapper(outlineMapper);
    outlineActor->GetProperty()->SetColor(colors->GetColor3d("Gray").GetData());
    outlineActor->GetProperty()->SetLineWidth(3);

    // Visualize
    vtkNew<vtkRenderer> renderer;
    vtkNew<vtkRenderWindow> renderWindow;
    renderWindow->AddRenderer(renderer);
    renderWindow->SetWindowName("IsoContours");

    vtkNew<vtkRenderWindowInteractor> interactor;
    interactor->SetRenderWindow(renderWindow);

    renderer->AddActor(contourActor);
    renderer->AddActor(outlineActor);
    renderer->SetBackground(colors->GetColor3d("Burlywood").GetData());

    vtkNew<vtkSliderRepresentation3D> sliderRep;
    sliderRep->SetMinimumValue(0.0);
    sliderRep->SetMaximumValue(30.0);
    sliderRep->SetValue(10.0);
    sliderRep->SetTitleText("Contour value");
    sliderRep->SetPoint1InWorldCoordinates(-20, -40, 0);
    sliderRep->SetPoint2InWorldCoordinates(0, -40, 0);
    sliderRep->SetSliderWidth(.2);
    sliderRep->SetLabelHeight(.1);

    vtkNew<vtkSliderWidget> sliderWidget;
    sliderWidget->SetInteractor(interactor);
    sliderWidget->SetRepresentation(sliderRep);
    sliderWidget->SetAnimationModeToAnimate();
    sliderWidget->EnabledOn();

    vtkNew<vtkSliderCallback> callback;
    callback->ContourFilter = contourFilter;

    sliderWidget->AddObserver(vtkCommand::InteractionEvent, callback);

    vtkNew<vtkInteractorStyleUser> style;
    interactor->SetInteractorStyle(style);

    renderWindow->SetSize(500, 500);
    renderWindow->Render();
    renderWindow->Render();
    interactor->Start();

    return EXIT_SUCCESS;

    return EXIT_SUCCESS;
}
namespace {
    void CreateData(vtkImageData* data)
    {
        data->SetExtent(-25, 25, -25, 25, 0, 0);
        data->AllocateScalars(VTK_DOUBLE, 1);
        int* extent = data->GetExtent();

        for (int y = extent[2]; y <= extent[3]; y++)
        {
            for (int x = extent[0]; x <= extent[1]; x++)
            {
                double* pixel = static_cast<double*>(data->GetScalarPointer(x, y, 0));
                pixel[0] = sqrt(pow(x, 2.0) + pow(y, 2.0));
            }
        }

        vtkNew<vtkXMLImageDataWriter> writer;
        writer->SetFileName("data.vti");
        writer->SetInputData(data);
        writer->Write();
    }
} // namespace